(a) Field of the Invention
The present invention generally relates to a method of preparing N-(2-aminoalkyl)-2-aminoethyoxylate ethane sulfonate.
(b) Description of the Prior Art
The following citations disclose compounds containing sulfonated diamines:
(bi) Germany patent nos. 2260870, 2551094, 2550797, 2900574, 3630045 and 3836030 disclose the use of sodium salt of N-(2-aminoethyl)-2-aminoethane sulfonic acid as emulsifying agent and chain extender for aqueous PU resins; PA1 (bii) Japan Publication No. 58-59959 discloses sulfonated diamine which can be obtained from the reaction of vinylsulfonic acid sodium salt with aliphatic diamines; and PA1 (biii) Germany patent no. 2035729 discloses the production of sulfonated diamines, from the reaction of ethylene diamine and propanesultone and then neutralize with an alkali to form sulfonated diamines, to form an aqueous PU dispersion, wherein its film has excellent water resistant properties. PA1 tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), 1,4-diisocyanato cyclohexane, 4,4'-diisocyanato dicyclohexylmethane (H.sub.12 MDI), isophorone diisocyanate (IPDI), tetramethylxylylene diisocyanate (TMXDI), diphenylmethane-4,4'-diisocyanate (MDI), toluylene diisocyanate (TDI), xylylene diisocyanate (XDI) and the mixture of the above diisocyanates.
In order to introduce an ethoxyl group into a sulfonated diamines, an alkali metal isethionate ethoxylate has to be synthesized first. The synthesis methods of these compounds have been taught in U.S. Pat. No. 2,535,678, which discloses the production of alkali metal isethionate ethoxylate by reacting sodium isethionate and triethylene glycol in the present of sodium hydroxide.
U.S. Pat. Nos. 4,091,014 and 4,226,807 disclose a preparation method of ether sulfonate. International Application No. PCT/US95/04178 has also discloses the preparation of alkali metal isethionate ethoxylate.